This proposal outlines the application of a combination of vacuum and far U.V. circular dichroism to an analysis of protein structure. Analysis of the CD data is to be performed by on line microprocessor and involves solution of the spectra in terms of the mutual configuration of adjacent peptide pairs (in phi, psi space). After checking the approach with known structures the method will be used to analyze the structure of various blood proteins including albumin, fibrinogen and particularly clotting factors. The research involves three stages: 1) construction of a vacuum U.V. CD instrument; 2) collection and correlation of (x-ray) known protein structures; 3) interpretation of blood protein structure.